添加CeO2对La2Mg17＋ 200％Ni贮氢电极的电化学性能研究  

Effects of addition of CeO_2 on electrochemical properties of La_2Mg_(17)+200% Ni composite alloy

作　　者：李霞[1,2] 许剑轶[2] 张胤[2] 张国芳[1,2] 王平[2] 

机构地区：[1]钢铁研究总院功能材料研究所,北京100081 [2]内蒙古科技大学内蒙古自治区白云鄂博矿多金属资源综合利用重点实验室,内蒙古自治区包头014010

出　　处：《电源技术》2013年第8期1342-1346,共5页Chinese Journal of Power Sources

基　　金：内蒙古自然科学基金资助项目(2011MS0803;2013MS0722)

摘　　要：研究了球磨时间及添加CeO2对La2Mg17+200%(质量分数)Ni复合合金相结构和电化学性能的影响。X射线衍射光谱法(XRD)结果表明,球磨100 h后Ni峰完全消失,合金完全非晶化,而过长的球磨时间会导致合金小颗粒的团聚和再次结晶化。少量CeO2的添加有助于非晶结构的形成。电化学性能表征显示,随着球磨时间从80、100、120 h时,复合合金放电比容量分别为326.9、352.1和352.6 mAh/g,添加CeO2后复合合金放电比容量再度提高到373.5、398.8和409.8 mAh/g,均提高40 mAh/g以上。但CeO2的加入对复合合金充放电循环稳定性的改善并不明显,结果表明:CeO2的加入,有效地降低了合金表面电化学反应阻抗,提高了贮氢合金的电催化活性,有助于提高放电容量。开路电位图也表明CeO2的加入不利于提高合金的抗腐蚀性能。The effects of ball-milling time and addition of CeO2 on microstructures and electrochemical properties of La2Mg17＋200% Ni composite alloys were investigated. The XRD results indicate that Ni peak disappears completely after ball milled 100 h, the structure of the alloy changes to amorphous, however, the longer ball milling time lead to the agglomeration and recrystallization. Small amount of CeO2 contributes to formation of amorphous structure. The characterization of electrochemical properties show that with the ball milling time increase from 80 h to 100 h and 120 h, the discharge specific capacities of La2Mg17＋200% composite alloy are 326.9, 352.1 and 352.6 mAh/g, respectively. When adding CeO2 to composite alloy, the discharge specific capacities increase again to 373.5, 398.8 and 409.8 mAh/g. But the addition of CeO2 to the composite alloy does not improve the cycling retention rate much. The electrochemical impedance spectroscopy （EIS） spectra demonstrates that the addition of CeO2 reduces the electrochemical reaction impedance of alloy surface effectively, which improves electrical catalytic activity of the hydrogen storage alloy, leads to the high discharge capacity. The open circuit potential also indicates that CeO2 ad verses to enhance alloy corrosion resistance.

关 键 词：贮氢合金 电化学性能 非晶态 球磨 

分 类 号：TM911[电气工程—电力电子与电力传动]